Solid-State Image Sensor Block Layout for Charge Addition Readout
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Solution Overview
Problem
In solid-state image sensors, the arrangement of floating diffusion layers and contact holes restricts the layout, leading to positional displacement between light received by different imaging devices, which hinders the addition of signals and increases sensitivity, making it difficult for image processing.
Innovation Solution
A solid-state image sensor configuration with multiple imaging device blocks, each containing photoelectric conversion layers and charge accumulating electrodes, where first and second charge movement controlling electrodes are provided to control charge transfer between and within blocks, allowing for the addition of signals from multiple photoelectric conversion devices without layout constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional solid-state image sensor layout with floating diffusion layers and contact holes is used, then manufacturing is simplified, but positional displacement occurs between light received by different imaging devices, preventing signal addition and reducing sensitivity
Solution Approach 1:
The patent transitions from a planar two-dimensional array of imaging devices to a three-dimensional stacked configuration where multiple imaging devices are arranged vertically across different layers. This dimensional change allows imaging devices to be positioned above semiconductor substrates rather than confined to a single plane, enabling signal addition without the positional displacement constraints of conventional lateral layouts.
Solution Approach 2:
The patent divides the imaging device structure into multiple discrete imaging devices, each with its own photoelectric conversion portion, arranged in separate stacks above different regions of the semiconductor substrate. This segmentation allows independent positioning and signal collection from each imaging device, which can then be added together to improve sensitivity while maintaining manufacturing precision.
2Reliability
If imaging devices are arranged in a stacked configuration, then signal addition capability is improved, but device complexity increases due to multiple charge movement controlling electrodes
Solution Approach 1:
The charge movement controlling electrodes are designed to perform multiple functions: they control charge transfer between imaging devices within a stack, manage charge movement between different stacks, and enable global shutter functionality. This multi-functionality reduces the need for separate dedicated electrodes for each function, thereby managing device complexity while maintaining signal addition capability.
Solution Approach 2:
The patent merges the control functions for charge movement between imaging devices and between stacks into a unified electrode system. The charge movement controlling electrodes are strategically positioned and configured to simultaneously manage charge transfer across multiple levels and stacks, consolidating what would otherwise require separate control mechanisms into a single integrated structure.
3Productivity
If multiple imaging devices share a common readout circuit, then productivity is improved, but charge may flow into adjacent devices causing interference
Solution Approach 1:
The charge movement controlling electrodes act as intermediaries between the photoelectric conversion portions and the readout circuits. These electrodes precisely control the timing and path of charge movement, ensuring that charges from different imaging devices are transferred to the appropriate readout circuits without flowing into adjacent devices. This intermediary control enables multiple imaging devices to share readout circuits efficiently while preventing charge interference.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables the addition of signals from multiple photoelectric conversion devices, enhancing sensitivity and simplifying the pixel region layout, while reducing charge flow into adjacent devices, thus improving image quality and allowing for global shutter functionality.
Implementation Method 1
a photoelectric conversion layer, an insulating layer, and a charge accumulating electrode arranged opposed to the photoelectric conversion layer
Data Source
AI summary
A solid-state image sensor includes a plurality of imaging device blocks each including P×Q imaging devices. In an imaging device block, first charge movement controlling electrodes are provided between the imaging devices, and second charge movement controlling electrodes are provided between the imaging device blocks. In the imaging device block, P imaging devices are arrayed along a first direction, and Q imaging devices are arrayed along a second direction. Charge accumulated in a photoelectric conversion layer of the (P−1)th imaging device from the first imaging device along the first direction is transferred to the photoelectric conversion layer of the Pth imaging device and read out together with charge accumulated in the photoelectric conversion layers of the Q Pth imaging devices, under the control of the first charge movement controlling electrodes.